A conventional, general wireless LAN system is disclosed in “Nikkei Communications”, issued on Sep. 2, 2002, Nikkei Business Publications, Inc. (p. 89, FIGS. 1-2).
FIG. 39 is a block diagram showing an exemplary configuration of the conventional wireless LAN system. The wireless LAN system has two communication areas A and B, an SW 70, electric cables 80a to 80e, access points (hereinafter referred to as APs) 90a to 90e, and terminals A and B. Also, the wireless LAN system is connected to the SW 70 to an external network (not shown).
The SW 70 switches an Ethernet® signal, which is input from an external network to the wireless LAN system, to each of the APs 90a to 90e. The electric cables 80a to 80e, which are, for example, Ethernet® twisted-pair cables, connect the SW 70 to the APs 90a to 90e. The APs 90a to 90e communicate with the terminal A or B using a wireless LAN signal. The terminals A and B are personal computers or PDAs (Personal Digital Assistants) which have a wireless LAN interface.
The area A is an area in which the APs 90a and 90b provide services. The area B is an area in which the APs 90c, 90d and 90e provide services. Note that no wireless LAN signal reaches from one of the areas A and B to the other.
Hereinafter, an operation of the wireless LAN system will be described.
Firstly, communication between the terminal A in the area A and the terminal B in the area B will be described. Here, it is assumed that the terminal A is connected to the AP 90b while the terminal B is connected to the AP 90e. 
The terminal A transmits a wireless LAN signal, which is in the form of a wireless radio wave, to the AP 90b. In response to this, the AP 90b receives the radio wave type wireless LAN signal. Next, the AP 90b converts the received wireless LAN signal to an Ethernet® signal, and transmits the resultant signal through the electric cable 80b to the SW 70.
The SW 70 memorizes the network structures of the areas A and B. The SW 70 transmits the received Ethernet® signal through the electric cable 80e to the AP 90e with reference to the memorized network structure. The AP 90e converts the Ethernet® signal transmitted from the SW 70 to a radio wave type wireless LAN signal, which is in turn transmitted to the terminal B. In this manner, the radio wave type wireless LAN signal transmitted by the terminal A reaches the terminal B. Note that a wireless LAN signal is transmitted from the terminal B to the terminal A in a manner reverse to that described above.
Next, communication of the terminal A with an external network will be described. The terminal A transmits a radio wave type wireless LAN signal to the AP 90b. In response to this, the AP 90b receives the wireless LAN signal. Next, the AP 90b converts the received radio wave type wireless LAN signal to an Ethernet® signal, which is in turn output to the SW 70. The SW 70 outputs the Ethernet® signal obtained from the AP 90b to the external network. Note that a signal input from an external network is transferred in a reverse direction to the terminal A.
Here, the area A has two APs, while the area B has three APs. If it is assumed that a single AP can accommodate ten terminals, twenty terminals can perform the above-described communication simultaneously in the area A and thirty terminals can perform the above-described communication simultaneously in the area B. Note that when an AP accommodates a plurality of terminals, the AP transmits/receives a signal from each terminal in a time division multiplex manner.
Note that, as used herein, accommodation capacity refers to the number of terminals on a system design. In other words, even if the number of terminals connected to an AP exceeds the accommodation capacity, it does not mean that the terminals can no longer perform communication, and the amount of a signal which can be transmitted to each terminal per unit time is only reduced.